package 剑指offer_leetcode;
/**
 * JZ69跳台阶
 */
public class 剑指Offer10_II_青蛙跳台阶问题 {
    public int numWays(int n) {
        if(n==0)
            return 1;
        if(n<=2)
            return n;
        int[] dp = new int[n+1];
        dp[0] = 1;
        dp[1] = 1;
        dp[2] = 2;
        for(int i=3;i<=n;i++)
            dp[i] = dp[i-1] %1000000007 + dp[i-2] % 1000000007;
        return dp[n] %1000000007;
    }
}
